Restores the tar command to its original state

What

This PR tries to reduce side effects by:

Restores the tar command to its original state
Narrow the ~/.cache directory to just nix and devbox

Why

We are using chmod u+s "$(command -v tar)" to setuid on tar (This is needed because we are caching /nix/ and other directories outside of ~, which is owned by root)

This has a problem where it changes the parent directory of ~/.cache/nix to be owned by root instead of runner.

I thought https://github.com/jetpack-io/devbox-install-action/pull/22 had fixed it, but we ran into similar issues when we use a go cache on top of the devbox cache.

Caveat

Cache enabled on self hosted Linux may stop working

jetify-com / devbox-install-action

Restores the tar command to its original state #21

What

Why

Caveat